Film cooling is one of the key techniques to improve the thermal performance of hot sections in gas turbines. Heat transfer coefficient is an important parameter to quantify the thermal performance, which is often analyzed based on the time averaged flow field. Nevertheless, in the case of film cooling, the mixing between the coolant and the main flow is inherently unsteady. To understand the mechanism of heat transfer, the current study uses large eddy simulation (LES) method to investigate the heat transfer coefficient of inclined jets in crossflow. The angle between the hole and the main flow is 35 degrees. Two different geometric holes, namely a cylindrical hole and a fan-shaped hole are investigated at a blowing ratio of 0.5, which is a typical value for film cooling application. Both the time averaged and the instantaneous flow characteristics are analyzed. The mechanism of heat transfer distribution is analyzed in detail. Near the surface, the streamwise fluctuated variables (u' T') over bar has a large effect on the heat transfer coefficient. Compared with the cylindrical hole, the heat transfer downstream of the fan-shaped hole is highly unsteady and streamwise fluctuated variables (u'T') over bar is larger, so the heat transfer coefficient is higher. (C) 2018 Elsevier Ltd. All rights reserved.